public ParameterHandler newParameterHandler(MappedStatement mappedStatement,
Object object, BoundSql sql, InterceptorChain interceptorChain){
    ParameterHandler parameterHandler =
    mappedStatement.getLang().createParameterHandler(mappedStatement,object,sql);
    parameterHandler = (ParameterHandler)interceptorChain.pluginAll(parameterHandler);
    return parameterHandler;
}
public Object pluginAll(Object target) {
    for (Interceptor interceptor : interceptors) {
        target = interceptor.plugin(target);
    }
    return target;
}

@Intercepts({
    @Signature(
    type = Executor.class,
    method = "query",
    args={MappedStatement.class,Object.class,RowBounds.class,ResultHandler.class}
    )
})
public class ExeunplePlugin implements Interceptor {
    //省略邏輯
}

<plugins>
  <plugin interceptor="com.zjq.plugin.ExamplePlugin"></plugin>
</plugins>

@Intercepts({//注意看這個(gè)?花括號(hào)，也就這說(shuō)這?可以定義多個(gè)@Signature對(duì)多個(gè)地?攔截，都?這個(gè)攔截器
    @Signature(type = StatementHandler.class , //這是指攔截哪個(gè)接?
    method = "prepare", //這個(gè)接?內(nèi)的哪個(gè)?法名，不要拼錯(cuò)了
    args = { Connection.class, Integer .class}),  //這是攔截的?法的?參，按順序?qū)懙竭@，不要多也不要少，如果?法重載，可是要通過(guò)?法名和?參來(lái)確定唯?的
})
public class MyPlugin implements Interceptor {
    // //這?是每次執(zhí)?操作的時(shí)候，都會(huì)進(jìn)?這個(gè)攔截器的?法內(nèi)
    @Override
    public Object intercept(Invocation invocation) throws Throwable {
        //增強(qiáng)邏輯
        System.out.println("對(duì)?法進(jìn)?了增強(qiáng)....");
        return invocation.proceed(); //執(zhí)?原?法
    }
    /**
    * //主要是為了把這個(gè)攔截器?成?個(gè)代理放到攔截器鏈中
    * ^Description包裝?標(biāo)對(duì)象 為?標(biāo)對(duì)象創(chuàng)建代理對(duì)象
    * @Param target為要攔截的對(duì)象
    * @Return代理對(duì)象
    */
    @Override
    public Object plugin(Object target) {
        System.out.println("將要包裝的?標(biāo)對(duì)象："+target);
        return Plugin.wrap(target,this);
    }
    /**獲取配置?件的屬性**/
    //插件初始化的時(shí)候調(diào)?，也只調(diào)??次，插件配置的屬性從這?設(shè)置進(jìn)來(lái)
    @Override
    public void setProperties(Properties properties) {
        System.out.println("插件配置的初始化參數(shù)："+properties );
    }
}

<mapper namespace="com.zjq.mapper.UserMapper">
    <!--sql語(yǔ)句抽取-->
    <sql id="selectUser">
      select * from user
    </sql>
    <select id="findByCondition" parameterType="user" resultType="user">
        <include refid="selectUser"></include>
        <where>
            <if test="id!=0">
                and id=#{id}
            </if>
            <if test="username!=null and username!=''">
                and username=#{username}
            </if>
            <if test="password!=null and password!=''">
                and password=#{password}
            </if>
        </where>
    </select>
  </mapper>

public class PluginTest {
    @Test
    public void test() throws IOException {
        InputStream resourceAsStream =
        Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession = sqlSessionFactory.openSession();
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        User condition = new User();
        //condition.setId(1);
        condition.setUsername("zjq");
        List<User> byPaging = userMapper.findByCondition(condition);
        for (User user : byPaging) {
            System.out.println(user);
        }
    }
}

// -Plugin
public Object invoke(Object proxy, Method method, Object[] args) throws
Throwable {
    try {
    /*
    *獲取被攔截?法列表，?如：
    * signatureMap.get(Executor.class), 可能返回 [query, update,
    commit]
    */
    Set<Method> methods = signatureMap.get(method.getDeclaringClass());
    //檢測(cè)?法列表是否包含被攔截的?法
    if (methods != null && methods.contains(method)) {
        //執(zhí)?插件邏輯
        return interceptor.intercept(new Invocation(target, method,
        args));
        //執(zhí)?被攔截的?法
        return method.invoke(target, args);
        } catch(Exception e){
    }
}

public class Invocation {
    private final Object target;
    private final Method method;
    private final Object[] args;
    public Invocation(Object targetf Method method, Object[] args) {
    this.target = target;
    this.method = method;
    //省略部分代碼
    public Object proceed() throws InvocationTargetException,
    IllegalAccessException { //調(diào)?被攔截的?法

<dependency>
  <groupId>com.github.pagehelper</groupId>
  <artifactId>pagehelper</artifactId>
  <version>3.7.5</version>
</dependency>
<dependency>
  <groupId>com.github.jsqlparser</groupId>
  <artifactId>jsqlparser</artifactId>
  <version>0.9.1</version>
</dependency>

<!--注意：分?助?的插件 配置在通?館mapper之前*-->*
<plugin interceptor="com.github.pagehelper.PageHelper">
  <!—指定?? —>
  <property name="dialect" value="mysql"/>
</plugin>

@Test
public void testPageHelper() {
    //設(shè)置分?參數(shù)
    PageHelper.startPage(1, 2);
    User condition = new User();
    //condition.setId(1);
    condition.setUsername("zjq");
    List<User> select = userMapper.findByCondition(condition);
    for (User user : select) {
        System.out.println(user);
    }
}

//其他分?的數(shù)據(jù)
PageInfo<User> pageInfo = new PageInfo<User>(select);
System.out.println("總條數(shù)："+pageInfo.getTotal());
System.out.println("總?數(shù)："+pageInfo. getPages ());
System.out.println("當(dāng)前?："+pageInfo. getPageNum());
System.out.println("每?顯示?度："+pageInfo.getPageSize());
System.out.println("是否第??："+pageInfo.isIsFirstPage());
System.out.println("是否最后??："+pageInfo.isIsLastPage());

<dependency>
  <groupId>tk.mybatis</groupId>
  <artifactId>mapper</artifactId>
  <version>3.1.2</version>
</dependency>

<plugins>
  <!--分?插件：如果有分?插件，要排在通?mapper之前-->
  <plugin interceptor="com.github.pagehelper.PageHelper">
    <property name="dialect" value="mysql"/>
  </plugin>
  <plugin interceptor="tk.mybatis.mapper.mapperhelper.MapperInterceptor">
    <!-- 通?Mapper接?，多個(gè)通?接??逗號(hào)隔開 -->
    <property name="mappers" value="tk.mybatis.mapper.common.Mapper"/>
  </plugin>
</plugins>

@Table(name = "t_user")
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;
    private String username;
}

import com.zjq.domain.User;
import tk.mybatis.mapper.common.Mapper;
public interface UserMapper extends Mapper<User> {
}

@Test
public void test1() throws IOException {
    Inputstream resourceAsStream =
    Resources.getResourceAsStream("sqlMapConfig.xml");
    SqlSessionFactory build = new
    SqlSessionFactoryBuilder().build(resourceAsStream);
    SqlSession sqlSession = build.openSession();
    UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
    User user = new User();
    user.setId(4);
    //(1)mapper基礎(chǔ)接?
    //select 接?
    //根據(jù)實(shí)體中的屬性進(jìn)?查詢，只能有一個(gè)返回值
    User user1 = userMapper.selectOne(user); 
    //查詢?nèi)拷Y(jié)果
    List<User> users = userMapper.select(null); 
    //根據(jù)主鍵字段進(jìn)?查詢，?法參數(shù)必須包含完整的主鍵屬性，查詢條件使?等號(hào)
    userMapper.selectByPrimaryKey(1); 
    //根據(jù)實(shí)體中的屬性查詢總數(shù)，查詢條件使?等號(hào)
    userMapper.selectCount(user); 
    // insert 接?
    //保存?個(gè)實(shí)體，null值也會(huì)保存，不會(huì)使?數(shù)據(jù)庫(kù)默認(rèn)值
    int insert = userMapper.insert(user);
    //保存實(shí)體，null的屬性不會(huì)保存，會(huì)使?數(shù)據(jù)庫(kù)默認(rèn)值
    int i = userMapper.insertSelective(user); 
    // update 接?
    //根據(jù)主鍵更新實(shí)體全部字段，null值會(huì)被更新
    int i1 = userMapper.updateByPrimaryKey(user);
    // delete 接?
    //根據(jù)實(shí)體屬性作為條件進(jìn)?刪除，查詢條件使?等號(hào)
    int delete = userMapper.delete(user);
    //根據(jù)主鍵字段進(jìn)?刪除，?法參數(shù)必須包含完整的主鍵屬性
    userMapper.deleteByPrimaryKey(1); 
    //(2)example?法
    Example example = new Example(User.class);
    example.createCriteria().andEqualTo("id", 1);
    example.createCriteria().andLike("val", "1");
    //?定義查詢
    List<User> users1 = userMapper.selectByExample(example);
}